A 45-year-old woman was admitted to our hospital complaining of a mass in her left breast. She had previously been diagnosed with myelodysplastic syndrome (MDS), a type of refractory anemia, based on bone marrow findings and chromosome analysis. She received a preoperative transfusion of fresh packed platelets and a recombinant human granulocyte colony-stimulating factor (rhG-CSF) injection. Left partial mastectomy and axillary lymph nodes dissection were performed to treat early breast cancer. Postoperatively, prophylactic radiotherapy of the residual breast and administration of medroxyprogesterone acetate (MPA) were performed because the tumor tissue was positive for progesterone receptors. She has remained clinically stable, with no evidence of recurrence, for more than three years to date. We report a rare case of breast cancer with MDS, treated with breast-conserving therapy. The strategy of pre- or postoperative platelet transfusion, rhG-CSF injections, and hormonal therapy (AAPA) appears to be suitable treatment for progesterone receptor (PgR)-positive breast cancer patients with AADS.